1. Technical Field
The present invention is directed to artwork images and the like and more particularly to glow in the dark artwork images produced from graphics art film or the like.
2. Description of the Prior Art
Many individuals adorn the walls of their businesses and homes with framed works of art. One artistic medium, used to produce images suitable for framing, is photographic or graphics art film. Such film contains small grains of silver bromide, evenly spread over a thin gelatin coating on a transparent surface. Light alters the silver bromide to produce light activated silver bromide: EQU AgBr+light.fwdarw.AgBr.sup.light
The film containing silver bromide that has been exposed to light (AgBr.sup.light) may then be treated with a solution containing a mild reducing agent (developer). In the redox process that follows, the Ag.sup.+ ions in the activated AgBr are preferentially reduced to metallic silver particles. The number of black metallic silver particles formed on the film is directly proportional to the amount of light exposure received by each area of the film. In this way a negative image may be formed. Such images are typically used to produce a positive print. These prints may then be framed for display.
Color prints and transparencies may also be produced. In order to produce a color image a film coated with three emulsion layers (responding respectively to blue, green, and red light) is used. A yellow filter layer is interposed between the first layer (blue sensitive) and the remaining two layers (green and red) in 1#order to prevent the blue light from adulterating the green and red layers. The emulsion layers contain chemicals which form dyes after being exposed to light.
Positive prints or transparencies are made in a reversal. The film is first developed to produce a negative in all three layers. Once the film has been developed it is successively exposed to a blue, green, and red light source. After each of these exposures the film is re-developed. The film is then bleached in order to produce a positive color print or transparency. Until now positive or negative film transparencies have not been associated with a luminescent layer.
Luminescence was first discovered by an alchemist in 1669. This process occurs when an atom of a luminescent material absorbs a photon of energy. This forces the atom into an excited state. As the atom moves from an intermediate energy state to its ground state a photon (having a lower energy and frequency than the absorbed atom) is emitted from the atom. There are two basic types of luminescent substances, namely, fluorescent and phosphorescent materials. Fluorescent materials emit visible light only after it has been bombarded with ultraviolet radiation. Phosphorescent materials continue to glow long after an illuminating source has been removed since excited phosphorous atoms may remain in a metastable state for several hours.
The process of forming glow in the dark images in also known in the art. For example, Switzer, U.S. Pat. No. 2,629,956 discloses a fluorescent printing method which utilizes novel fluorescent dyes applied so as to form an image on the viewing surface of a non-image producing substrate. Likewise, Dudnick, U.S. Pat. No. 4,708,817 discloses a method of forming latent luminescent image patterns on the viewing surface of a wide variety of substrates.
The resulting luminescent images produced by both the Switzer and Dudnick methods require the use of special luminescent materials adapted for use on particular types of substrates. Additionally, the luminescent images produced by these methods is applied primarily as paint in a luminescent image producing pattern on a particular medium, and only secondarily, if at all, as paint in a luminescent image producing pattern to luminesce an already image producing medium. Furthermore, both disclosures teach the application of a luminescent paint or dye to the front or viewed surface of a particular medium. Finally, neither Switzer nor Dudnick disclose the use of photographic film to produce glow in the dark transparencies.